Extraversion, 260n16
Eyes, 50–51, 56–58
Eysenck, Hans Jürgen, 221, 260n16
Fireflies, 88
Foster, Russell, 51, 56, 59
Frequency demultiplication, 127–128
Frisch, Karl von, 261n4
Fruit flies, 63–64, 70, 72, 82, 241n2, 242n4, 250n6
Fuller, C. A.: The Clocks that Time Us, 238n1
Gauss, Carl Friedrich, 236n9
Gender, 11, 101–102, 235n1
Genes, 231, 243n8, 247n3; activation of, 2, 14, 75–80; mutations of, 60–65, 68–69, 72–73, 219, 228, 239n5, 241n3, 242n7, 243nn1,2, 249n5, 261n6; clock genes, 63–64, 68–74, 82–83, 117, 118, 166, 219, 242n4, 243n1, 250n6; and disease, 212, 248n2; and sleep duration, 219; Smith-Magenis syndrome, 220, 259n10; and sex, 235n1; and nucleotides, 241n3; dominant genes, 243n7; recessive genes, 243n7; semi-dominant genes, 243n7; human genome, 245n11; alteration during lifetime, 252n1. See also Proteins
Germany: Bavaria, 41, 109, 157, 170, 252n8; former German Democratic Republic (GDR), 152–155, 158–160, 162, 170, 231, 251nn1,7; Saxony-Anhalt, 152–155, 251n2; chronotypes in, 156–160, 169, 177, 231; Baden-Wuerttemberg, 170, 252n8; industrialization in, 210
Gonyaulax polyedra, 81–89, 246nn5,7
Gravitaxis, 84–85
Greenwich Mean Time, 2, 161
Gronfier, Claude, 118, 127
Gwinner, Eberhard, 226–227, 261n3
Hardin, Michael, 70, 71
Harrington, Mary, 88–89
Harvard University: Hastings’s lab at, 4–5, 83–84; sleep research at, 92–93, 216
Hastings, Woody, 4–5, 247n8
Health: relationship to biological clock, 1, 2, 171, 230; relationship to shift work, 156–157, 188–192; relationship to sleep, 217–218
Heterozygotes, 243n8
Hippocrates, 221, 260n14
Holst, Erich von, 41, 247n3
Homozygotes, 243n8
Honey bees, 261n4
Honma, Sato, 17
Hormones: and body clock, 2, 14–15, 41, 43, 58, 79, 104, 238n1; testosterone, 14–15, 102; melatonin, 58, 104, 188–190, 220, 222, 240n10, 255n3; cortisol, 79, 104; and age, 102; and puberty, 235n3
Human reproduction, 208–212, 257nn10–13
Immune system and sleep, 26, 171, 213, 217–218, 257n14
India, 155, 187, 192, 199, 251n6, 255n3
Indolamines, 188, 254n1, 255n2
Industrialization, 210–212, 231
Infradian rhythms, 247n1
Insects, 58, 262n8
Internal desynchronization, 38–46, 86, 132–133
Interns, 216, 258nn2,3
Isocaloric meals, 104, 248n7
Jet lag, 1, 133–138, 141, 147–148, 149, 231, 249nn1,3, 250n6. See also Social jet lag
Johnson, Carl, 86–87, 246n8
Joshi, Amitabh, 18
Journal of Biological Rhythms, 88
Jupiter, 115, 116, 127–128
Kay, Steve, 250n6
Konopka, Ron, 63
Kretschmer, Ernst, 221, 260n15
Latitude, 207–209
Leaf movements, 31–35, 40, 49, 78, 238n1
Leap years, 19
Light-at-night (LAN) hypothesis, 188–190, 255n3
Light–dark cycle: vs. internal time, 40, 42, 45–46, 48–51, 49, 59, 60–65, 114–128, 118, 132–134, 137, 141–143, 148–151, 155–160, 166–167, 213, 227, 231, 242n6, 249n2, 250n6; as zeitgeber, 118–128, 136, 148, 155, 166–167, 249n2; amplitude of, 166–167, 252n3
Lingulodinium polyedrum, 81–89. See also Gonyaulax polyedra
Linné, Carl von, 247n2
Liver, 74, 75–78, 79–80, 137
Longitudinal studies, 256n5
Lorenz, Konrad, 41, 247n3, 261n4
Luciferase, 250n6
Lunar cycle, 19, 237n5
Lunchtime dip, 78, 93, 94–95, 109–110
Magazine articles, 14–15
Mairan, Jean Jacques d’Ortous de, 31–35, 40, 45–46, 49, 78, 231, 238n1
Mania, 219
Mars, 115, 116–117, 118, 125, 127, 133
Masking, 240n6
MCTQ. See Munich ChronoType Questionnaire
Measurement, 173–176
Melanopsin, 57, 59, 74, 240n8
Melatonin, 58, 104, 220, 222, 240n10; light-at-night (LAN) hypothesis regarding, 188–190, 255n3
Menaker, Michael, 242n5, 249n6
Mercury (planet), 115, 125
Merrow, Martha, 108, 110
Messenger RNA (mRNA), 72, 244nn4,6
Metabolism, 75, 80, 244n1, 245n9
Metabolites, 80, 245n9
Midnight, 19, 20, 161, 252n10
Millar, Andrew, 250n6
Modafinil, 237n1
Molecules, 70–72
Months, 19, 20
Moore-Ede, M. C.: The Clocks that Time Us, 238n1
Morningness–eveningness preference, 221–222, 260n17
Morning routines, 8–12
Mortality and the seasons, 208, 257n9
Mueller, Chris, 245n7
Munich ChronoType Questionnaire (MCTQ), 104, 170–171, 178, 196; database size, 100–101, 156, 235n6; vs. sleep logs, 143, 177, 253n3; Web access to, 236n6, 247n1; vs. morningness–eveningness preference questionnaire, 260n1
Napoleon, 218
Naps, 218–219
Narcolepsy, 112, 248n2
Neptune, 115, 116, 117, 118, 127, 133
Netherlands, 187
Neurospora crassa, 242n4
Neuroticism, 259n12, 260n16
Newborns, 98
New York stock exchange, 21
Nocturnal animals, 58, 62–63, 79, 137, 229–230, 240n4
Noon, 19, 20–21
Nucleotides, 241n3
Nutrition, 247n3, 256n5
Opsin, 57, 80, 241n3
Optical illusions, 223
Optic chiasm, 50, 58, 240n2
Oscillators, biological clocks as, 26–27, 28, 29, 42–46, 119–120, 237n2
Outsourcing, 187–188
Oxygen radicals, 188, 254n2
Peer review process, 257n1
Personality, 215, 219–222, 260n16
Philippines, 187–188
Phosphorylation, 243nn1,2, 244n5
Photoperiods, 206, 207–210, 211, 213, 256n4, 257n14
Photosynthesis, 246n3, 254n2
Phototaxis, 84–85, 86; positive vs. negative, 246n4
Physiological stress, 188, 189, 191
Pineal gland, 58, 240n9
Pittendrigh, Colin, 40–41, 63
Plants, 31–35, 40, 49, 57–58, 78, 238n1, 254n2, 262n8
Polysomnographic recordings, 254n6
Pöppel, Ernst, 5
Population density, 169–170
Problem-based learning, 6
Prokaryotes, 242n4, 261n7
Proteins, 79–80, 243n2, 244n6, 245n11, 252n1; clock proteins, 69, 70, 72, 74, 80, 82–83; and Western blots, 77–78, 245n3; as transcription factors, 241n3, 244n4. See also Genes
Puberty, 11, 101, 103, 235n3, 248n4
Ralph, Martin, 65, 242n5
Rasmunson, Svenja, 115–117, 121, 127
Reptiles, 58, 262n9
Retina: rods and cones, 50–51, 56, 57, 59; melanopsin, 57, 59, 74
Rodents, 102, 240n4; wheel-running activity of, 51–52, 53, 55–56, 58, 60–65, 68–69, 241n1, 250n6
Rosbash, Michael, 70–71
Saturn, 115, 116, 127–128
Schibler, Ueli, 245n7
Schizophrenia, 212
School hours, 105, 106–113, 151, 218, 230
SCN. See Suprachiasmatic nucleus
Scotoperiod, 256n4
Seasons of the year, 20, 92, 202–213, 237n6; relationship to time of dawn, 8, 9–10, 11, 19; and DST, 177–179, 182; seasonal affective disorder (SAD), 206–207; relationship to suicide rates, 207; relationship to general mortality, 208, 257n9; relationship to birth rates, 208–212
Sex, 11, 78, 88, 235n1; and hormones, 14–15; sex chromosomes, 243n7
Shift work
, 21, 49, 58, 59, 115, 148, 184–192, 231; relationship to health, 156–157, 186–187, 188–192; and outsourcing, 187–188; physiological stress of, 188, 189, 191; and light-at-night (LAN) hypothesis, 188–190; and chronotype, 190–192; and social isolation, 191–192
Siestas, 94, 128, 136
Single-cell organisms, 1, 2–3, 5, 80, 81–89, 228, 231, 242n4, 261n7
Sleep: duration, 12, 14, 21–23, 141–143, 144–148, 183, 204, 206, 217–219, 221; timing, 12–14, 21–23, 25–30, 141, 144–148; midsleep, 12–14, 22, 42, 104, 149, 150, 157–158, 196, 236n8; on free days vs. work days, 13, 139–148, 151, 177–183, 187; relationship to tiredness, 25, 26–27, 28–30; relationship to time of day, 26, 28–30; relationship to immune system, 26, 171, 213, 217–218, 257n14; deprivation, 27, 28–30, 103–105, 136, 142–143, 146, 149, 216, 219–220, 237n1, 258nn2,3; sleep pressure, 27–28, 29–30, 92–93, 94, 105; forbidden zone for, 30, 236n4; relationship to body temperature, 39–40, 42, 43–44, 86, 93–94; problems with, 47–48, 59; and the brain, 74; during Stone Age, 90–91, 103; as episodic, 92; relationship to age, 95, 96–105, 247n1; ultradian sleep pattern, 98–99; micro-sleep, 112; REM sleep, 112, 238n3, 248n3; and DST, 177–183; quality of, 217–218; relationship to health, 217–218; naps, 218–219. See also Chronotype; Sleep–wake cycle
Sleep–wake cycle, 2, 24–30, 90–95, 136, 225, 227, 238n1; on free days vs. work days, 13, 139–148, 151, 177–183, 187; in Andechs bunker experiments, 36–46, 52–53, 54, 86, 94; and suprachiasmatic nucleus, 58; relationship to age, 95, 96–105, 247n1. See also Chronotype; Sleep
Smith-Magenis syndrome, 220, 259n10
Smoking, 151
Social jet lag, 1, 149–151, 183, 187, 218, 222
Social time: defined, 1–2; vs. internal time, 1, 136, 141, 148–149, 155–162, 176–183, 190–191, 259n7; and social jet lag, 1, 149–151, 183, 187, 218, 222; DST, 160, 161, 173–183, 203, 231, 253n4, 254nn7–8
Space, 223–226
Spain, industrialization in, 210–211
Sports medicine, 249n3
Standard European Time (SET), 178–179, 180, 253n4, 254n7
Stone Age, 90–91, 103
Subjective time, 44–45, 238nn1,4
Suicide rates, 207
Sulzman, F. M.: The Clocks that Time Us, 238n1
Sundials, 254n9
Sunrise, 173, 253n1
Sun time, 1–2, 91, 160, 252n11; vs. internal time, 2, 156–160, 177
Suprachiasmatic nucleus (SCN), 58, 65, 72, 74, 78, 93, 137, 240nn12,13
Synchronization of body clocks: by light–dark cycle, 98, 114–128, 148–149, 155–160, 166–167, 190, 191, 231, 239n1, 249n2; by food, 137; by social cues, 148–149, 155, 158–160, 231, 239n1. See also Entrainment; Internal desynchronization
Synechococcus elongatus, 87, 246n8
Teachers, 216–217
Teenagers, 106–113; chronotypes of, 100, 101–104, 110–113, 151, 196, 217, 230; disco hypothesis regarding, 102–103, 111, 161–162, 218, 251n6
Temperature, 208–212, 213, 228–229, 252n12, 256n4. See also Body temperature
Testosterone levels, 14–15, 102
Thermoclines, 246n1
Tides, 19, 20
Time and space, 224–225
Time zones, 1–2, 133, 134–135, 136, 140–141, 157, 160. See also Jet lag
Tinbergen, Niko, 247n3, 261n4
Toemmelt, Olaf, 152–154
Tokyo stock exchange, 21
Transcription factors, 241n3, 244n4, 245n8
Twenty-four hour day, 19–21, 29–30, 38–40, 45–46, 237n1; vs. free running body clock, 40, 42–43, 48–50, 52–53, 54, 59, 60–65, 121–122, 242n6; vs. days on other planets, 114–117, 118, 127–128
Twins, 163–166, 171–172
Ultradian rhythms, 98–99, 247n1
Uranus, 115, 116, 117, 127
Van Someren, Eus, 98–99
Variations in internal time, 2, 5, 15, 46, 60–65, 72–73
Venus, 125
Waggle dance, 261n4
Wake maintenance zone, 30, 236n4
Wake-up types, 10, 11–12
Wall Street stock exchange, 21
Wehr, Tom, 202–205, 213, 256n1
Well-being and internal time, 1, 2, 7, 45, 46, 171, 231
Western blots, 77–78, 245n3
Wever, Rüdger, 41, 48–49, 239n1
Work days vs. free days: sleep on, 139–148, 151, 177–180; and DST, 177–183; of shift workers, 187
Work schedules, 230. See also Shift work
Wuarin, Jérome, 245n7
Yawning, 247n4
Year length, 19–20
Zeitgebers: light–dark cycle, 118–128, 136, 148, 155, 166–167, 249n2; strength of, 136, 166–171, 190, 253n4; defined, 249n2
Zeitraum days, 226, 227, 229–230, 261nn2,5
Copyright © 2012 by DuMont Buchverlag
All rights reserved
Jacket image: Bridgeman Art Library International
Jacket design: Jill Breitbarth
First published in German translation as Wie wir ticken: Die Bedeutung der inneren Uhr für unser Leben, copyright © 2010 by DuMont Buchverlag,
Cologne (Germany)
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book and Harvard University Press was aware of a trademark claim, then the designations have been printed in initial capital letters.
Library of Congress Cataloging-in-Publication Data
Roenneberg, Till.
[Wie wir ticken. English]
Internal time : chronotypes, social jet lag, and why you’re so tired /
Till Roenneberg.
p. cm.
Subtitle of original German text: Die Bedeutung der inneren Uhr
für unser Leben.
Includes bibliographical references and index.
ISBN 978-0-674-06585-7 (alk. paper)
1. Chronology. 2. Biological rhythms. I. Title.
QP84.6.R64 2012
612′.022—dc23 2011050230
Internal Time: Chronotypes, Social Jet Lag, and Why You’re So Tired Page 26
